Journal:Acta Cryst D:S2059798322001772
From Proteopedia
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The bacterium ''Mycobacterium tuberculosis'' infects one-quarter of the entire human population, resulting in more than a million deaths from Tuberculosis each year. In their cell walls, Mycobacteria synthesize abundant, related cell wall glycolipids called phosphatidyl-''myo''-inositol mannosides (PIMs), lipomannans (LMs) and lipoarabinomannans (LAMs), which interact with the infected host. This paper describes the first crystal structure of LmcA, a recently identified Mycobacterial protein that converts PIMs into LMs and LAMs, via an unknown mechanism. | The bacterium ''Mycobacterium tuberculosis'' infects one-quarter of the entire human population, resulting in more than a million deaths from Tuberculosis each year. In their cell walls, Mycobacteria synthesize abundant, related cell wall glycolipids called phosphatidyl-''myo''-inositol mannosides (PIMs), lipomannans (LMs) and lipoarabinomannans (LAMs), which interact with the infected host. This paper describes the first crystal structure of LmcA, a recently identified Mycobacterial protein that converts PIMs into LMs and LAMs, via an unknown mechanism. | ||
| - | The LmcA structure revealed an elongated beta-barrel fold and one alpha-helix extending away from the beta-barrel core. <scene name='90/906221/Cv/7'>The crystal structure of MSMEG_0317</scene> adopts an extended beta-barrel core composed of 11 antiparallel beta-strands with two alpha-turns and one alpha-helix extending away from the core. The secondary structure elements are shown in distinct colours. Interestingly, <scene name='90/906221/Cv/20'>two distinct cavities</scene> were found inside the protein which could bind a ligand. Further analysis revealed elements in LmcA that may undergo conformational changes to ‘open’ the protein, permitting access to the cavities. <scene name='90/906221/Cv4/6'>Comparison of MSMEG_0317 (white) with MSMEG_0317-Xe (pink) highlights changes in loop 9 conformation to a more "open" state due to xenon binding</scene>. <scene name='90/906221/Cv4/7'>This scene without animation</scene>. While the ligand remains to be identified, comparison of the crystal structure with LmcA models from other bacterial species suggests a common mechanism of ligand binding involving the cavities. These findings provide new structural insights into the biosynthetic pathway for PIM/LM/LAM, essential components of the mycobacterial cell surface. | + | The LmcA structure revealed an elongated beta-barrel fold and one alpha-helix extending away from the beta-barrel core. <scene name='90/906221/Cv/7'>The crystal structure of MSMEG_0317</scene> adopts an extended beta-barrel core composed of 11 antiparallel beta-strands with two alpha-turns and one alpha-helix extending away from the core. The secondary structure elements are shown in distinct colours. Interestingly, <scene name='90/906221/Cv/20'>two distinct cavities</scene> were found inside the protein which could bind a ligand. Further analysis revealed elements in LmcA that may undergo conformational changes to ‘open’ the protein, permitting access to the cavities. <scene name='90/906221/Cv4/6'>Comparison of MSMEG_0317 (white) with MSMEG_0317-Xe (pink) highlights changes in loop 9 conformation to a more "open" state due to xenon binding</scene>. <jmol><jmolButton> |
| + | <script>if (_animating); anim pause;set echo bottom left; color echo white; font echo 20 sansserif;echo Animation Paused; else; anim resume; set echo off;endif;</script> | ||
| + | <text>Stop Animation</text> | ||
| + | </jmolButton></jmol> <scene name='90/906221/Cv4/7'>This scene without animation</scene>. While the ligand remains to be identified, comparison of the crystal structure with LmcA models from other bacterial species suggests a common mechanism of ligand binding involving the cavities. These findings provide new structural insights into the biosynthetic pathway for PIM/LM/LAM, essential components of the mycobacterial cell surface. | ||
<b>References</b><br> | <b>References</b><br> | ||
Revision as of 12:25, 13 March 2022
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